Troubleshooting Adler Barbour CU100 and CU200 Refrigeration Units




     Unnecessary gadgets on newer models of icebox conversion refrigeration units increase costs and affect systems reliability. This Tech Tip deals with failures of an extra not required electrical circuit board on Adler Barbour CU 100 and CU 200 module systems.

     Initial reports by captains vary from intermittent cooling or compressor tries to start every minute but stops running and others report three or four flashes of trouble warning Red LED. When this LED flashes a code of three it is because control module sees a much higher than normal amperage and it then prevents compressor from running. In each company’s documentation a three signal code maybe described differently, now we know that poor connections inside Adler Barbour’s Stainless steel box can also trigger a three flash code too. Many times it is reported when a service technician is called he will not be able to correctly diagnose this problem. To charge for service call he readjusts refrigerant volume or advised compressor is bad. After handling a few of these troubling incidents of AB printed circuit board failures a visual non destructive check first would be smart. Failures of circuit board inside stainless steel box so far seem to be Female 15 amp fuse plug to check remove fuse and look in fuse opening for heat discoloration. Next gently check the green plastic area outside box where boat’s plus and minus power wires are connected. Picture #1 shows printed circuit burnt through near negative boat wiring connections. Other failures are fuse holder and solder connections where red and yellow power wires to Danfoss module are connected. If it has been confirmed that circuit board is defective visually there are three options to get refrigeration back in operation:


              a. Order a new circuit board from Dometic Marine

              b. Temporally bypass power or ground wire.

              c. Remove stainless gadget box completely and wire according to Danfoss’s more reliable standard wiring.

     If add on circuit board visually looks good then I would eliminate standard Danfoss troubleshooting items 1 through 4 before bypassing circuit board in stainless steel box wiring.


STANDARD TESTS for Danfoss BD Compressors


      1. The first and easiest item to eliminate would be thermostat by placing a jumper wire across Danfoss control module terminals           C and T. If thermostat is digital instead of standard or non standard speed control device is connected to C and T terminals repair person may not want to tamper with these units without talking to manufacturer.

     Smart Danfoss electronic control modules take the place of all safety devices found on large refrigeration like: High and Low pressure switches, Thermo overloading by heat amperage and High or Low voltages.

     2. To eliminate low voltage signal of one flash that might be covered up by a three flash overload do to attempts by module to restart compressor turn of system for five minutes then restart and watch for first LED code. If first code is one flash then there is a problem with boats power grid. To eliminate a boat wiring problem run fused correct size and correct polarity jumper wires direct from a fully charged battery in order to bypass all boat’s wiring. Volt meter readings are of no value when looking for voltage spikes.

     3. Next item to eliminate is electronic compressor control module place it on another Danfoss BD type system. An experienced tech will carry a spare module on his truck. If there is no way to test module I can test them you pay only shipping.

     4. Although fan circuit overload of ½ amp is not normally linked to compressor not running without a two LED flash code it can be eliminated on CU systems by removing the 5 amp fuse and disconnecting wire connected to Danfoss control module terminal F.


     UNDERSTANDING and TESTING Adler Barbour add on Circuit Board



Before checking circuits inside Adler Barbour’s stainless steel box you need to understand what is inside.

  • A relay, on back of board intended to be used to allow expansion of ½ amp module fan circuit to power additional fans if required on CU100 models or a water pump on CU200 models.
  • Wiring for Troubleshooting LED
  • A 3 amp fuse on back of board is only used when standard thermostat is replaced with a Digital type unit for its power source.
  • The four wires to thermostat female Phone jack yellow and green wires for standard mechanical thermostat. Black and Red wires are for power to optional Digital thermostat

    After completing visual check of circuit board inside stainless steel box and then completing tests 1 through 4 without discovering why compressor is not running both power wires through box need to be bypassed. But first make sure the boat’s power fuse or circuit breaker for this refrigerator is no larger than 15 amps because you will be bypassing 15 amp fuse protection inside stainless box.

    To bypass Power around add-on stainless box first remove Red large + wire from Danfoss control module.

Disconnect battery power from green board + terminal and reconnect it to Danfoss module large + terminal.

With thermostat set to cold turn breaker or switch on. Compressor should run if trouble was caused by loss of power as it passed through circuit board. With no positive + power inside box LED and fan will not work be powered and on CU200 water pump will not have power.

    Next, again with power turned off and because there were at least three failures of ground wires reported as it passed through circuit boards causing at lest one sending a three flash overload code. To bypass ground circuit test is the same as power wire test. Remove battery ground from Danfoss Module and ground wire from green plastic circuit board and connect battery ground direct to Danfoss – terminal. Disconnecting and connecting wires are always done with power turned OFF ELIMINATE COMPLETELY ELIMINATE Stainless Box and Board Circuit Board Inside.

      1. On Danfoss standard module 101N0210 top terminal is -- Boat ground wire.

      2. On Danfoss module 101N0210 second terminal down is + Power from refrigerator 15 amp 12/24 volt DC boat’s circuit breaker or fuse.

      3. Third terminal down is a small+ this is for Red power wire from fan and is limited to 1/2 amp. It is also used for power + wire of LED. Most LEDs require a resistor so they can handle 12 volts I recommend a $2.90 Red 12 volt LED at Radio shack P/N 276-0270 comes with built in resistor and Red and black wires simplifying installation. Because there now will be two wires connected to Small + terminal a dual spade connector is needed to connect fan and LED together. Resistor on board removed is for that LED but it is not required if board is gone. Compressor speed resistor is at thermostat end of wire and not involved with box removal.

      4. Fourth terminal down marked F is for black fan wire.

      5. Fifth terminal down D is for LED ground wire.

      6. Sixth terminal down is thermostat terminal C has green thermostat wire connected to it.

      7. Seventh terminal down P has no wire on it.

      8. Bottom terminal T is for the other thermostat Yellow.(yellow)

Once completed wiring of module is as recommended by Danfoss for BD35 and BD50 compressors.

     Picture 1 is of the board removed from a system displaying a three LED flash Code. Failure occurred on printed circuit strip near ground wire screw and Yellow  (yellow) wire to Danfoss module top ground terminal.